Messages in this thread | | | Subject | Re: [PATCH net-next] xfrm: policy: Remove obsolete WARN while xfrm policy inserting | From | Yuehaibing <> | Date | Thu, 9 Apr 2020 16:19:37 +0800 |
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On 2020/4/6 17:03, Steffen Klassert wrote: > On Mon, Mar 30, 2020 at 10:05:32PM +0800, Yuehaibing wrote: >> On 2020/3/28 19:23, Steffen Klassert wrote: >>> On Fri, Mar 27, 2020 at 08:34:43PM +0800, YueHaibing wrote: >>>> Since commit 7cb8a93968e3 ("xfrm: Allow inserting policies with matching >>>> mark and different priorities"), we allow duplicate policies with >>>> different priority, this WARN is not needed any more. >>> >>> Can you please describe a bit more detailed why this warning >>> can't trigger anymore? >> >> No, this warning is triggered while detect a duplicate entry in the policy list >> >> regardless of the priority. If we insert policy like this: >> >> policy A (mark.v = 3475289, mark.m = 0, priority = 1) //A is inserted >> policy B (mark.v = 0, mark.m = 0, priority = 0) //B is inserted >> policy C (mark.v = 3475289, mark.m = 0, priority = 0) //C is inserted and B is deleted > > The codepath that replaces a policy by another should just trigger > on policy updates (XFRM_MSG_UPDPOLICY). Is that the case in your > test?
Yes, this is triggered by XFRM_MSG_UPDPOLICY
> > It should not be possible to add policy C with XFRM_MSG_NEWPOLICY > as long as you have policy B inserted. > > The update replaces an old policy by a new one, the lookup keys of > the old policy must match the lookup keys of the new one. But policy > B has not the same lookup keys as C, the mark is different. So B should > not be replaced with C.
1436 static bool xfrm_policy_mark_match(struct xfrm_policy *policy, 1437 struct xfrm_policy *pol) 1438 { 1439 u32 mark = policy->mark.v & policy->mark.m; 1440 1441 if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m) 1442 return true; 1443 1444 if ((mark & pol->mark.m) == pol->mark.v && //policy is C, pol is B, so mark is 0, pol->mark.m is 0, pol->mark.v is 0 1445 policy->priority == pol->priority) //priority is same zero, so return true, B is replaced with C 1446 return true; 1447 1448 return false; 1449 }
Should xfrm_policy_mark_match be fixed?
> >> policy D (mark.v = 3475289, mark.m = 0, priority = 1) >> >> while finding delpol in xfrm_policy_insert_list, >> first round delpol is matched C, whose priority is less than D, so contiue the loop, >> then A is matched, WARN_ON is triggered. It seems the WARN is useless. > > Looks like the warning is usefull, it found a bug. > > > . >
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